Emeléus et al., disclose synthesis of diiodosilane (SiH2I2) by reaction of Silane (SiH4), Hydrogen Iodide (HI), and aluminum iodide (AlI3). Derivatives of monosilane. Part II. The Iodo compounds: Emeleus, H. J.; Maddock, A, G.; Reid, C., J. Chem. Soc. 1941, 353-358). The reaction produces the desired SiH2I2 reaction product along with Iodosilane (SiH3I), Triiodosilane (SiHI3), and tetraiodosilane (SiI4). Id. at p. 354.
Keinan et al. disclose the reaction of iodine and phenylsilane in a 1:1 molar ratio in the presence of traces of ethyl acetate at −20° C. produces 1 mol of SiH2I2 and 1 mol of benzene. J. Org. Chem., Vol. 52, No. 22, 1987, pp. 4846-4851. Although selective for SiH2I2 over the other possible iodosilanes (i.e., SiH3I, SiHI3, and SiI4), this method produces the known human carcinogen benzene, which makes commercial implementation difficult. Despite this drawback, it remains the preferred synthetic approach to producing Diiodosilane.
A need remains for a less hazardous SiH2I2 synthesis method that yields large volumes of the SiH2I2 product (i.e., and few to no volumes of the other iodosilanes: SiH3I, SiHI3, and SiI4).